I like to drive my '67 230SL fast (don't we all)? Lately, on the interstate, 80 mph is pretty common. When I drive it in the Kansas summer heat (93 degrees today), I can watch the water temperature go above 185 F and move into the 200+ range. I note that the redline on temperature is somewhere around 240 F. I don't have anyone local to compare with, so I ask for input. Is this normal? Since my 80 MPH crusing is for short periods of time (15-20 minutes), the temperature drops back down pretty quickly when the rpm goes down. Does the radiator need flushing? Is the water pump working efficiently?
Now for part two. After the temperature is elevated from high speeds, I can come to an idle and watch the oil pressure drop from 45 psi (needle pegged), down to 30 psi. A little rev on the gas will make it go back to maximum pressure, but it gives me the impression that some internals are expanded (from the heat) to the point that there is a loss of pressure. Is this a sign of something major about to need work? Should I not push my baby too hard? I changed the oil to Valvoline 20w-50w, to make it handle the summer temperatures better.
The engine has 93,000 miles on it. Records show no significant repairs (like rings or valves, etc.).
